Concrete roadway.



E. M. CHADBOURNB.

CONCRETE ROADWAY.

APPLICATION HLED'JULY 19,1910.

Patented J an. 24, 1911.

2 SHEETS-.SHEET 1.

E. M. CHADBOURNE.

GONGRETE ROADWAY.

APPLIUATION FILED JULY 19,1910.

982,247. Patented 1111.211911 2 SHEETS-SHEET 2.

www @1,

ED *sTATns EDWARD M. cH-ADBOURNE, on SAN rRANcisco, CALIFORNIA.

i [.conenrn ROADWAY..`

,l Specication of Letters'lleatent. Patented Jan. 24, 191.1

Application led July 19,1910. Serial No. 572,728.

` San Francisco and State of California, have invented .a certain new and useful Improvement 1n, Concrete Roadways; and I do herel bydeclare lthe. following `to be a full, clear,

and exact description of the same, reference being had to the accompanying. drawings, forming a part of this specification, and to the figures and letters ofreference marked thereon.

lhis invention relatesto the construction f ofpaving for roadways, streets, walks, etc., embodying a 'suitable foundation for supporting and distributing the load and a surfacing or top'layer of wear resistant mate- .ri'al or composition.

Objects of the invent-ion are toprovide a paving which Will be dustless and have a' Well bonded waterproof surface-of such -/character as to afford greaty resistance to Wear under all conditions of traffic without kbeing slippery when wet. l

Further objects `of the invention are Ato reduce the cost of paving having the vdesirable qualities mentioned and to provide for Vits construction and the combining of the ingredients at thel place'where the paving` is laid, thereby avoiding the necessity of `preliminary mixing and preparation in plants at lixed points and subsequent transf portationof the. mixed ingredients to the place of use.

In accordance with the present invention v a suitable foundation, such 'for instance as a reinforced concrete foundation is laid on y a suitable sub-grade,\ said foundation being preferably substantially impervious to oils fund in asphaltic binders now in common use or of the character hereinafter referred .'to. The asphaltic binder employed is preferably a heavy asphaltic oil which is practically non-fluid at normal temperatures but liquees when heated to a temperature of 1750 or over. .This asphaltic binder is heated and poured -or'is s read directly on the surface of the base'an retained thereon preferably by suitable surrounding Walls suchas 'would be'formed by pockets in the; surface of the foundation or by forms of wood, iron, cardboard, etc., placed onthe top of the foundation.

Over the binder there is placedy a layer of clean dry rock Vscreenings ,which are artithen rolled or compressed forcing the screenv ings downwardly and the asphaltic binder upwardly to fill the voids in the/screenings.-

The screenings being het the binder will thoroughly coat the same and forma bond therewith which is insoluble and' nnal'ected by atmospheric or weather conditions.`

y In practical paving operationstlie screenings are preferably heated 'in situ by a port-- able burner arranged to shoot a flame down into the same thereby thoroughly heating the same and also liquefying-the heavy asphalticv binder. IVhile the screenings are still hot and the binder in a liquid state the mass is compressed by rollingtherebv forcing the screenings down and the binder Vupwardly so as to lill the yoids and form a wearing layer having superior wear resisting qualities, and a surface best calculated to afford perfect traction without tendency to disintegrate orr break down in use or because of atmospheric or climatic conditions.

The heater or burneremployed may be of any of the kindsl employed lfor heating aspha 'roadways in repair Work as now practiced, although I- dofnot Wish to be understood vas limiting the invention to vany particular meansI for or meth of heating the screenings preliminary to t e forcing of the same down into the asphaltic binder.

In the accompanying drawings-Figlires 1, 2, 3, and 4; are sectional views through sections ofavements or roadways in variousstages o construction in accordance with the resent invention.

T e letter A in said drawings indicates the foundation which may be of Aa 1.2.5 concrete mix, laid on a suitable sub-grande B and having embedded therein metal reinforcement C. The top 'surface of the foundation is in the illustrations formed with pockets orv binder retaining means by havin `partially embedded therein stone or rock contained in the aggregate. This stone or rock may be of approxlmately egg size and is spread over the -oundation whi e thel lat* -ter is still,` plasticf and suitably.' rolled or tamped so as to bel artiall embedded or of somewhat larger size than that icc anchored in thefonation, t ereby forming l binder retaining pockets oriwalls of ap roximately an inch 1n depth, as shown c early f in Fig. l. V y

When the foundation is .set suliiciently,

the heavy asphaltic oil binder which may contain more than 85 asphalt and preferably previously heated suiciently to How, is

Aspread over the base so as to partly or wholly fill the pockets, the appearance then being somewhat as shown in Fig 2, where the letter E indicates the binder. In Fig. 3 the letter F indicates the clean screenings which may besubstantially of a size which will pass a screen of one half inch mesh. After being. heated as before described and rolled it is found that the screenings have been forced down and the asphaltic binder up. All voids are filled by the relative upward? movement of the binder thereby driving out the air and mak# inga practically homogeneous layer. y

he heating of the screenings or small size aggregate not only insuresthe reduction of the binder to a limpid condition, but it drives off any moisture that may be present and causes the binder to intimately unite with the surface of each/particle of aggregate` as the latter is forced down and the binderup in the voids or interstices in the aggregate. f Roadways may be laid in accordance with the present invention even when the prevailig temperature is very low and use may be made of a binder having a much largery percentage of asphalt .or liquefying solid matter than heretofore, thereby not only reducing the cost but increasing the lifepand wear resisting qualities of the pavement.

Having thus described my invention, what I claim as new and desire t0 secure by Let-- ters Patent of the United States is- 1.V The method of pavement construction which consists in laying a foundation substantially impervious to heavy oils and with oil retaining receptacles on its upper face; in s reading 'thereon a heated cementitious bin er in liquid condition and which is substantially non-fluid at normal temperatures4 and in applying and pressing into the layer of cementitious binder a layer of heated screenings whereby the screenings are forced down` and the binder rendered limpid and displaced upwardly to fill the voids in and bond the screenings together.

2. The method of which consists in laying a foundation substantially impervious to heavy oils and with oil retaining receptacles on its up er face; in s reading thereon a heavyasplialtic oil in a eated and liquid condition but which is non-fluid at normal temperatures; ins reading over the binder a layer of sma llsize aggregate;4 in heating Athe'layers of aggregate and binder and finally in applying pressure to force the aggregate down and displace the binderupwardly to fill the voids in and bond the aggregate together. 3. vThe method of avement construction `which consists in laying a concrete foundation .and forming its surfa'ceinto oil retain. ing receptacles; in spreading thereon a heavy asphaltic oil binder rendered liquid by heat but which is .substantially non-fluid at normal temperatures; a'nd in forcing down into said binder a layer of heated small size aggregate ywhereby the binder is rendered limpid, coats the particles of aggregate and is displaced upwardly to ll the voids in and bond the aggregate together.

4. The method Ofpavement construction5 which consists inv laylng alconcrete foundation, in adding material to the top of the foundation to form receptacles, in applying a cementitious binder of heavy asphaltic oil previously liquefied by heating; in applying a layer of small size aggregate, then heating the aggregate and binder to render the binder' more limpid and finally rolling the surface to force the aggregate down into the binder and displace the binder upwardly yto till the voids in the aggregate.

EDWARD M. CHALQBOURNE.

Witnesses ANNA R. Conan, ROBERT SoHoRR.

avement construction- 

